Fig. 7.

A model of the proposed substrate in the binding site of WbmF. (a) Overview of modelled interaction of WbmF with the 4-keto derivative of UDP-d-ManNAc3NAcA. Protein is shown as cartoon, with key (labelled) side chains, NAD and sugar nucleotide in sticks. The elements of the UDP-sugar found in the experimental structure have paler colours to highlight the modelled sections. (b) and (c) Close-up of the modelled sugar ring (shown as spheres) demonstrates that there are no clashes between the proposed ligand and the protein surface. The two views show opposite sides of the sugar: (c) shows the surface with the imaged slab cut at the level of the first sugar atom, with NAD surface also removed for clarity. Carbon atoms are yellow for protein, white for the NAD and cyan for 4-keto UDP-d-ManNAc3NAcA; oxygen is red, nitrogen is blue, phosphorus is orange and sulfur is purple.